The first person on Mars might be a grandmother. That's one unexpected possibility discovered by an all-female, six-member international crew that has just returned from Mars, or a reasonable facsimile of it, in the Utah desert.

The all-female Mona Lisa Project is the second half of an all-male, then all-female crew experiment by the Mars Society.

The experiment is being held in the remote Mars Desert Research Station to see how different groups perform under conditions resembling those of the Red Planet.

The project recognises that one of the biggest obstacles to a human mission to Mars is not technical, it's human nature.

"I think the all-female crew bonded together very quickly," says Mona Lisa commander Anne Pacros, a French aerospace engineer for the European Space Agency.

"We always took care of each other, making sure everybody was fine and happy with the group decisions."

Two weeks on Utah's 'Mars' wasn't nearly as long or as isolating as a real trip to Mars, crew members report.

But it was a chance to conduct a range of scientific experiments, explore the desert dressed in simulated pressure suits and perform a wide range of tasks that would likely be required of any crew that landed on Mars for the first time.

"The critical question is whether a single sex crew is easier or harder to deal with," saus crew psychologist Sheryl Bishop, associate professor at the University of Texas.

It was Bishop who became a grandmother during the project.

Same-sex crews have some advantages, Bishop says, because crew members can relate to each other a lot better.

"What we see in practice is that when things are good, same gender groups form cohesive teams," says Bishop.

"When there are problems, such as some team members not fitting in well or disagreements and conflict, same gender teams don't deal as well ... as mixed-gendered teams where there is a greater variety of interpersonal 'resources' to draw upon."

So does the Mona Lisa Project make it any more likely that the first human on Mars will be a woman? Probably not, says Bishop.

"Despite all the evidence supporting women as equally (and in some respects, more so) capable in dealing with microgravity and the challenges of space, there are agencies ... [that] characterised women as 'too fragile' to be included in a mission to Mars," says Bishop.

That attitude will likely change, given enough time, and Bishop holds out hope for her new granddaughter.

"Who knows?" Bishop says. "Perhaps she will be that first human on Mars."